sandbox: cros-ec: Add tests for the Chromium OS EC PWM driver

This patch adds a limited pulse-width modulator to sandbox's Chromium OS
Embedded Controller emulation. The emulated PWM device supports multiple
channels but can only set a duty cycle for each, as the actual EC
doesn't expose any functionality or information other than that. Though
the EC supports specifying the PWM channel by its type (e.g. display
backlight, keyboard backlight), this is not implemented in the emulation
as nothing in U-Boot uses this type specification.

This emulated PWM device is then used to test the Chromium OS PWM driver
in sandbox. Adding the required device node to the sandbox test
device-tree unfortunately makes it the first PWM device, so this also
touches some other tests to make sure they still use the sandbox PWM.

Signed-off-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

1 files changed, 47 insertions, 0 deletions

diff --git a/drivers/misc/cros_ec_sandbox.c b/drivers/misc/cros_ec_sandbox.c
index bc01df0904..db5e3b0f51 100644
--- a/drivers/misc/cros_ec_sandbox.c
+++ b/drivers/misc/cros_ec_sandbox.c
@@ -64,6 +64,7 @@ struct ec_keymatrix_entry {
 
 enum {
 	VSTORE_SLOT_COUNT	= 4,
+	PWM_CHANNEL_COUNT	= 4,
 };
 
 struct vstore_slot {
@@ -71,6 +72,10 @@ struct vstore_slot {
 	u8 data[EC_VSTORE_SLOT_SIZE];
 };
 
+struct ec_pwm_channel {
+	uint duty;	/* not ns, EC_PWM_MAX_DUTY = 100% */
+};
+
 /**
  * struct ec_state - Information about the EC state
  *
@@ -85,6 +90,7 @@ struct vstore_slot {
  * @recovery_req: Keyboard recovery requested
  * @test_flags: Flags that control behaviour for tests
  * @slot_locked: Locked vstore slots (mask)
+ * @pwm: Information per PWM channel
  */
 struct ec_state {
 	u8 vbnv_context[EC_VBNV_BLOCK_SIZE_V2];
@@ -98,6 +104,7 @@ struct ec_state {
 	bool recovery_req;
 	uint test_flags;
 	struct vstore_slot slot[VSTORE_SLOT_COUNT];
+	struct ec_pwm_channel pwm[PWM_CHANNEL_COUNT];
 } s_state, *g_state;
 
 /**
@@ -554,6 +561,33 @@ static int process_cmd(struct ec_state *ec,
 		len = sizeof(*resp);
 		break;
 	}
+	case EC_CMD_PWM_GET_DUTY: {
+		const struct ec_params_pwm_get_duty *req = req_data;
+		struct ec_response_pwm_get_duty *resp = resp_data;
+		struct ec_pwm_channel *pwm;
+
+		if (req->pwm_type != EC_PWM_TYPE_GENERIC)
+			return -EINVAL;
+		if (req->index >= PWM_CHANNEL_COUNT)
+			return -EINVAL;
+		pwm = &ec->pwm[req->index];
+		resp->duty = pwm->duty;
+		len = sizeof(*resp);
+		break;
+	}
+	case EC_CMD_PWM_SET_DUTY: {
+		const struct ec_params_pwm_set_duty *req = req_data;
+		struct ec_pwm_channel *pwm;
+
+		if (req->pwm_type != EC_PWM_TYPE_GENERIC)
+			return -EINVAL;
+		if (req->index >= PWM_CHANNEL_COUNT)
+			return -EINVAL;
+		pwm = &ec->pwm[req->index];
+		pwm->duty = req->duty;
+		len = 0;
+		break;
+	}
 	default:
 		printf("   ** Unknown EC command %#02x\n", req_hdr->command);
 		return -1;
@@ -619,6 +653,19 @@ void sandbox_cros_ec_set_test_flags(struct udevice *dev, uint flags)
 	ec->test_flags = flags;
 }
 
+int sandbox_cros_ec_get_pwm_duty(struct udevice *dev, uint index, uint *duty)
+{
+	struct ec_state *ec = dev_get_priv(dev);
+	struct ec_pwm_channel *pwm;
+
+	if (index >= PWM_CHANNEL_COUNT)
+		return -ENOSPC;
+	pwm = &ec->pwm[index];
+	*duty = pwm->duty;
+
+	return 0;
+}
+
 int cros_ec_probe(struct udevice *dev)
 {
 	struct ec_state *ec = dev_get_priv(dev);